Mastic or joint cement is applied to flat wall joints by tools popularly known to drywall finishers as "Ames Boxes" developed in the late 1940's and disclosed in U.S. Pat. Nos. 2,824,442; 2,984,857 and 3,888,611 to R. G. Ames. The Ames boxes greatly cut the time of finishing out flat joints but did little to speed the cost of finishing the outside corners. One of the more recent changes in the industry that has increased the cost of production to the contractor and piece worker has been the increased use of corner trim or corner beads. Corner beads are broadly defined as strips of plastic or metal to reinforce and finish corners, angles, or ends of wallboard.
Special tools have been developed for the application of mastic or cement to outside corners as disclosed in U.S. Pat. No. 4,230,441 to J. D. Heronema and U.S. Pat. No. 4,451,223 to M. F. Mower and E. R. Johnson. It should be readily apparent that such special tools may be costly to acquire and that maintenance required to prepare the tools for use and the cleanup after use will be time
U.S. Pat. No. 4,907,955 to J. T. Snipes discloses a drywall finishing tool having pivoted corner guide members mounted on both opposite end walls of the housing in which the mastic is contained. The corner guide members can be used to engage an edge corner in some cases, especially where a wider application of plaster is desired. The pivoted guide members are intended to be moved to inactive positions, however, when other attachments on the tool are used. There is no suggestion that the pivoted guide members in the form disclosed are applicable to flat boxes of the type disclosed in the Ames U.S. Pat. No. 2,824,442. It is also noted that the pivoted guide members are applied to the Snipes U.S. Pat. No. 4,907,955 without any provision being made for friction wear shoes on the leading edges of the flat box end walls as disclosed in the above-mentioned Ames patent.
Many drywall craftsman applying mastic or cement to wall joints or as finishing coats on wall boards use an "Ames" flat box or other equivalent brand tools.
Accordingly, it is an object of the present invention to provide simple and inexpensive adapters to enable "Ames" flat boxes, or other like brand tools, to be used to successfully fill an outside corner bead.
It is further object to provide adapters that can easily be fitted to flat boxes sold under trade names such as "AMES", "TAPE TECH", "TAPE MASTER" and the like to enable the flat boxes to be used to fill corner beads at a much faster rate than the manual pan and knife methods normally used.
It is a further object of the present invention to provide adapters to be fitted to a flat boxes that will enable one person to fill more corner bead with mastic in an hour than could normally be done by two or three men using the conventional method.
It is yet a further object of the present invention to provide adapters for tools commonly used in the industry by drywall finishers that makes the tools capable of quality production increases without the expense of additional tools or flat box modifying devices.
It is yet a still further object of the invention to provide adapters that easily adapt already available and familiar tools to a further use as a tool for filling corner beads with mastic without affecting its originally designed use as a basic tool for filling flat joints and coating flat wall board surfaces.
It is yet a further object of the invention to provide adapters that allows flat boxes to be operated on wall board flat surfaces when the corner guide edges on the adapters are in a retracted position or on an outside corner bead when the guide edges by a simple adjustment are moved to an extended position.
It is yet a further object to provide adapters that can be fitted to the leading edges of the flat box end walls with provision for friction shoes and flexible troweling bar guide retention in sidewall recesses.
These and other objects will be apparent from the following disclosure of a preferred embodiment of the present invention.